ProposalContrast: Unsupervised Pre-training for LiDAR-based 3D Object Detection

Existing approaches for unsupervised point cloud pre-training are constrained to either scene-level or point/voxel-level instance discrimination. Scene-level methods tend to lose local details that are crucial for recognizing the road objects, while point/voxel-level methods inherently suffer from limited receptive field that is incapable of perceiving large objects or context environments. Considering region-level representations are more suitable for 3D object detection, we devise a new unsupervised point cloud pre-training framework, called ProposalContrast, that learns robust 3D representations by contrasting region proposals. Specifically, with an exhaustive set of region proposals sampled from each point cloud, geometric point relations within each proposal are modeled for creating expressive proposal representations. To better accommodate 3D detection properties, ProposalContrast optimizes with both inter-cluster and inter-proposal separation, i.e., sharpening the discriminativeness of proposal representations across semantic classes and object instances. The generalizability and transferability of ProposalContrast are verified on various 3D detectors (i.e., PV-RCNN, CenterPoint, PointPillars and PointRCNN) and datasets (i.e., KITTI, Waymo and ONCE).Comment: Accepted to ECCV 2022. Code: https://github.com/yinjunbo/ProposalContras

SCN5A Variants: Association With Cardiac Disorders

The SCN5A gene encodes the alpha subunit of the main cardiac sodium channel Nav1.5. This channel predominates inward sodium current (INa) and plays a critical role in regulation of cardiac electrophysiological function. Since 1995, SCN5A variants have been found to be causatively associated with Brugada syndrome, long QT syndrome, cardiac conduction system dysfunction, dilated cardiomyopathy, etc. Previous genetic, electrophysiological, and molecular studies have identified the arrhythmic and cardiac structural characteristics induced by SCN5A variants. However, due to the variation of disease manifestations and genetic background, impact of environmental factors, as well as the presence of mixed phenotypes, the detailed and individualized physiological mechanisms in various SCN5A-related syndromes are not fully elucidated. This review summarizes the current knowledge of SCN5A genetic variations in different SCN5A-related cardiac disorders and the newly developed therapy strategies potentially useful to prevent and treat these disorders in clinical setting

Genetic Evidence for an Indispensable Role of Somatic Embryogenesis Receptor Kinases in Brassinosteroid Signaling

The authors are grateful to the Arabidopsis Biological Resource Center for providing the T-DNA insertion lines discussed in this work. We thank Dr. Yanhai Yin (Iowa State University) for providing anti-BES1 antibody, Dr. Jiayang Li (Institute of Genetics and Developmental Biology, Chinese Academy of Sciences) for bri1-301 seeds, and Dr. Xing-wang Deng (Yale University) for cop1-4 and cop1-6 seeds as controls.Author Summary Brassinosteroids (BRs) are a group of plant hormones critical for plant growth and development. BRs are perceived by a cell-surface receptor complex including two distinctive receptor kinases, BRI1 and BAK1. Whereas BRI1 is a true BR-binding receptor, BAK1 does not appear to have BR-binding activity. Therefore, BAK1 is likely a co-receptor in BR signal transduction. The genetic significance of BAK1 was not clearly demonstrated in previous studies largely due to functional redundancy of BAK1 and its closely related homologues. It was not clear whether BAK1 plays an essential role or only an enhancing role in BR signaling. In this study, we identified all possible BAK1 redundant genes in the Arabidopsis thaliana genome and generated single, double, triple, and quadruple mutants. Detailed analysis indicated that, without BAK1 and its functionally redundant proteins, BR signaling is completely disrupted, largely because BRI1 has lost its ability to activate downstream components. These studies provide the first piece of loss-of-functional genetic evidence that BAK1 is indispensable to the early events of the BR signaling pathway.Yeshttp://www.plosgenetics.org/static/editorial#pee

Radiolabeling and Biological Evaluation of Novel 99mTc-Nitrido and 99mTc-Oxo Complexes with 4-Methoxy-L-Phenylalanine Dithiocarbamate for Tumor Imaging

To develop novel radiolabeled amino acid tumor imaging agents, 4-methoxy-L-phenylalanine dithiocarbamate (MOPADTC) was synthesized successfully, and two kinds of 99mTc-labeled complexes ([99mTc]TcN-MOPADTC and [99mTc]TcO-MOPADTC) with high radiochemical purities (RCP > 95%) were obtained. The in vitro stability and partition coefficient were determined, and the results show that both of these complexes have good in vitro stability; [99mTc]TcO-MOPADTC is hydrophilic, while [99mTc]TcN-MOPADTC is slightly lipophilic. The biodistribution of [99mTc]TcN-MOPADTC and [99mTc]TcO-MOPADTC in mice bearing S180 tumors shows that the tumor uptake and tumor/muscle ratio of [99mTc]TcO-MOPADTC were higher than the tumor uptake and tumor/muscle ratio of [99mTc]TcN-MOPADTC. In addition, the tumor retention of [99mTc]TcO-MOPADTC is better than the tumor retention of [99mTc]TcN-MOPADTC. A competitive inhibition assay was performed, and the results indicate that [99mTc]TcO-MOPADTC may enter cells primarily via the L-alanine/L-serine/L-cysteine (ASC) system. Single-photon emission computed tomography (SPECT) imaging of [99mTc]TcO-MOPADTC shows obvious accumulation in tumor sites, suggesting that [99mTc]TcO-MOPADTC is a novel potential tumor-imaging agent